Method and composition for applying a covering to a wall or like substrate

ABSTRACT

Method and composition for applying a surface covering to a wall or like substrate. The surface covering comprises a flexible strip or sheet of substantially dry, semi-hydrated gypsum, bonded to a re-enforcing mesh or lath. The method includes the steps of coating the rear face of the surface covering sheet with aqueous latex adhesive in an amount which will transfer sufficient water from the adhesive to the gypsum to hydrate and set the gypsum, and, at the same time, invert the latex to a tacky, adherent state; and applying the adhesive-coated surface covering to the substrate.

United States Patent [191 Swedenberg et a1.

1 June 3, I975 METHOD AND COMPOSITION FOR APPLYING A COVERING TO A WALLOR LIKE SUBSTRATE [76] Inventors: Clyde ,1. Swedenberg, 3706 E. NorthSt. Ext., Greenville, S.C. 29607; Charles C. Fain, Bayphone Estates,Clemson, S.C. 29631; William W. Rutledge, 33 W. Tallulah Ave.,Greenville, S.C. 29601 22 Filed: Aug. 26, 1971 21 Appl. No.: 175,388

[52] US. Cl. 428/247; 106/111; 156/39; 156/71; 156/333; 428/921;428/140;

[51] lnt. Cl B32b 13/00 [58] Field of Search 161/182, 247, 270, 403,161/406, 167, 159, 160, 161, 167, 113, 89;

[56] References Cited UNlTED STATES PATENTS 2,421,721 6/1947 Smith et a152/408 2,657,163 10/1953 Ericks 156/41 3,106,500 10/1963 Turner 156/713,185,297 5/1965 Rutledge: 156/71 3,382,119 5/1968 Henkel 156/713,578,548 5/1971 Wesp 161/160 3,647,609 3/1972 Cyba 161/160 OTHERPUBLICATIONS Gold Bond, Technical Bulletin No. 2171, December 1964,A.I.A. File No. 23-L, National Gypsum Company, page 6.

Primary Examiner-George F. Lesmes Assistant Examiner-S. SilverrnanAttorney, Agent, or F irmBailley & Dority [5 7] ABSTRACT 11 Claims, N0Drawings METHOD AND COMPOSITION FOR APPLYING A COVERING TO A WALL ORLIKE SUBSTRATE BACKGROUND OF THE INVENTION U.S. Pat. No. 3,185,297 showsa surface covering or building wall material which includes asemi-hydrated gypsum. A strip of such material is typically applied to awall or other substrate and spraying or coating sufficient water to asheet of the material to hydrate the gypsum and cause it to set andharden. While this material can be adequately applied by a skilledworker, the novice or amateur worker frequently has difficulty ingauging the appropriate quantity of water which should be added.Typically, the novice adds a large excess of water which will run intothe floor and otherwise create a mess. The extra water causes the gypsumto sag and displace.

SUMMARY OF THE INVENTION In accordance with the present invention, theamount of water added to the gypsum can be closely controlled and, atthe same time, additional adhesive is supplied in a tacky form whichwill greatly facilitate handling the sheet material and applying it tothe substrate. Sagging of the gypsum and dripping of water iseliminated. The surface covering will quickly bond to the substratewithout requiring any substantial bonding time.

The surface covering is typically intended for covering an unfinishedwall, such as is formed by concrete blocks. The gypsum will desirably beprovided on its front face with a reenforcing mesh or lath which can begiven a wallpaper treatment for decorative purposes.

In its semi-hydrated form, the mixture of gypsum and binder is soft andflexible, as is the lath. Accordingly, the surface covering can befurnished in roll form, taking up little space and facilitatinghandling.

At the site of application, the surface covering is unrolled and acoating of latex adhesive is brushed or rolled onto the rear surfacethereof in an amount suffi cient to hydrate and set the gypsum andinvert the latex. The adhesive coated gypsum sheet is then applied tothe substrate.

Other objects, features and advantages of the invention will appear fromthe following disclosure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the disclosure hereofis detailed and exact to enable those skilled in the art to practice theinvention, the physical embodiments herein disclosed merely exemplifythe invention, which may be embodied in other specific structure. Thescope of the invention is defined in the claims appended hereto.

The disclosure of U.S. Pat. No. 3,185,297 is incorporated herein byreference. Said patent discloses a building wall material or surfacecovering suitable for use in accordance with the present invention.Commercial embodiments of said patent frequently omit the fiber batt 5of said patent and the lath will typically comprise a fabric mesh on thefront face of the gypsum layer, which re-enforces the gypsum and mayalso constitute an external surface therefor which faces the room togive decorative and wallpaper effects. The covering masks and finishesany rough and unfinished substrate over which the covering is applied,such as concrete block, concrete walls, etc.

As aforestated, the surface covering is typically fursum-binder isflexible. A sheet or strip of surface covering is unrolled to a desiredsize and the rear surface thereof is coated with an aqueous latexadhesive in an amount which will transfer sufficient water from theadhesive to the gypsum to hydrate and set the gypsum and, at the sametime, remove sufficient water from the adhesive to invert the latex andconvert it to a viscous, tacky state, ideally suited to adhere the wallcovering firmly to the substrate.

Inasmuch as the entire hydration requirements of the gypsum are suppliedby the aqueous latex adhesive, it is unnecessary to supply or otherwiseadd water to the gypsum. The addition of water is thus closelycontrolled and all mess and over-hydration is avoided.

There is a wide variety of various latex adhesives that are suitable foruse in the present invention. However, a polyvinyl acetate wateremulsion has performed admirably because of its ease of formulation,price and ultimate physical propertiesf Other latex adhesives which arealso suitable include: vinylacetate-ethylene copolymers, polyvinylchloride, polymers or copolymers of acrylic acid,acrylonitrile-butadiene copolymers, chlorinated rubber, neoprene,polyisobutylene, SB-R rubber, Butyl rubber.

The polyvinyl acetate in the preferred formulation typically consists offrom 45-60% solids, the balance being water.

It is also desirable, but not essential, that a latex plasticizer beincluded in the adhesive. Suitable plasticizers include: Abalyn, acetyltributyl citrate, butyl benzyl phthalate, butyl phthalyl butylglycolate, dibutyl phthalate, dibutyl sebacate, diethyl phthalate,diethylene glycol dibenzoate, diphenyl phthalate, dipropylene gylcol,dipropylene glycol dibenzoate, ethyl phthalyl ethyl glycolate, hexyleneglycol, cresyl diphenyl phosphate.

In addition or in lieu of the plasticizer, a latex solvent may beincluded. Typical suitalble solvents include: ethanol, isopropanol,methanol, carbon tetrachloride, chloro-benzene, ethylene dichloride,methylene chloride, perchloro-ethylene, trichloroethylene, ethylacetate, dioxane, benzene, toluene, xylene, acetone, methyl ethylketone, nitrobezene, tetrahydrofuran.

To increase the adhesive characteristic of the coating, a tackifyingresin may be included in the formulation. Suitable tackifying resinsinclude: Abalyn, belro, dresinol emulsions, Poly-pale esters, vinsol,Nevillac.

If desired, a thickener can also be added to the formulation. Suitablethickeners include: casein, guargum, gumarabic, hydroxyethylcellulose,methylcellulose, polyvinyl alcohol, starches. Additionally, a tireretardant additive can be included in the formulation. Additivessuitable for this purpose include: cresyl diphenyl phosphate, cresylphenyl phosphate and tricresyl phosphate. A biocide can also be includedin the formulation, if desired. Suitable biocides include: phenol,formaldehyde, and santobrite.

Typical general formulations of latex adhesive, by weight, are given inthe following examples:

Polyvinyl acetate water emulsion 30 95 parts (45% solids) Plasticizer 515 parts Water 0 20 parts Example II Polyvinyl acetate water emulsion 3095 parts (45% 60% solids) Solvent 5 35 pans Water 25 parts Example IllPolyvinyl acetate water emulsion 30 95 parts (45% 60% solids)Plasticizer parts Solvent 0 35 parts Water 0 25 parts Example IVPolyvinyl acetate water emulsion 30 95 parts (45% 60% solids) Tackifyingresin 1 parts Water 0 30 parts Example V Polyvinyl acetate wateremulsion 3O 95 parts (45% 60% solids) Thickener l 20 parts Water 0 30parts Example VI Ethylene-vinyl acetate copolymer water emulsion (45%60% solids) 30 95 parts Plasticizer 5 l5 parts Water 0 20 parts ExampleVII Ethylene-vinyl acetate copolymer water emulsion (45% 60% solids) 3095 parts Tackifying resin 1 20 parts Water 0 50 parts For optimumresults, substantially all of the requirements of the gypsum for watershould be satisfied by the water present in the adhesive and enough ofthe water should be removed from the adhesive to invert the latex.

Three parts of water are usually required to set ten parts of gypsumplaster by weight. Accordingly, if, for example, the gypsum layer of thesurface covering has fourteen ounces of plaster per square yard, 4.2ounces of water should be supplied in the adhesive per square yard whenthe adhesive coating is applied. Assuming an adhesive with a realviscosity of forty poise, 15 square yards of surface covering materialis coated with one gallon of adhesive. This means that 8.5 ounces ofadhesive is applied per square yard of the gypsum. Assuming the adhesivecontains 49% water, this will result in a sufficient quantity of waterin the adhesive to hydrate and set the plaster. By the same token, anadhesive of one hundred poise, which covers ten square yards per gallon,must have a water content of 34% to completely hydrate and set thegypsum.

Ideally there should be an excess of about 10% water in the adhesive toallow for loss due to evaporation, handling and shipping.

In for foregoing examples, water is present both in the water emulsionand in the additional water component of the formulation.

In the foregoing examples, a sufficient quantity of water has beentransferred from the latex emulsion to the gypsum to cause inversion ofthe latex. Typically, removal of 65 of the water from a polyvinylacetate water emulsion adhesive will cause inversion. In the case ofpolyvinyl acetate, the adhesive will typically change from a white,milky-appearing liquid (5 lOO poise viscosity) to a clear, semi-solid(about 100,000 poise viscosity) within a few seconds of application tothe gypsum and transfer of water thereto. The effect is the productionon the rear face of the wall covering of a continuous film of tackyadhesive somewhat in the nature of a pressure-sensitive film. Prior tocoating the gypsum, the adhesive has low viscosity and low tack, thusmaking it easily-handled and applied. However, within a few secondsafter application to the gypsum, the adhesive has the characteristics ofa high-viscolsity and highly tacky adhesive. The covering is thusadhered to the substrate substantially instantaneously and with ease andfacility by the worker.

We claim:

1. A decorative wall covering for installation upon a rigid wall forimparting a finished surface to the wall consisting essentially of:

a. a flexible lath of mesh material,

b. a substantially dry semi-hydrated flexible gypsum layer bonded onsaid material substantially covering one side of said lath,

c. a substantially uniform aqueous latex adhesive coating across anexposed side of said gypsum layer for securing said wall covering tosaid rigid wall and hydrating said gypsum,

d. said ratio of aqueous latex adhesive to gypsum is such that saidaqueous latex adhesive supplies about three parts by weight of water forabout ten parts of weight of gypsum, and

e. said semi-hydrated flexible gypsum being of sufficient thickness thatsaid aqueous latex adhesive affords a sufficiently controlled amount ofwater to hydrate said gypsum and for inverting said latex adhesive,

whereby the wall covering may be shipped and stored in rolls preparatoryto installation utilizing said application of aqueous latex adhesive.

2. The combination of claim 1, in which the aqueous latex adhesiveincludes a latex plasticizer.

3. The combination of claim 1, in which the aqueous latex adhesiveincludes a tackifying resin.

4. The combination of claim 1, in which the aqueous latex adhesiveincludes as thickener.

5. The combination of claim 1, in which the aqueous latex adhesiveincludes a biocide.

6. The combination of claim 1, in which the aqueous latex adhesiveincludes a fire-retardant additive.

7. The combination of claim 1, in which the aqueous latex adhesivecomprises a water emulsion of polyvinyl acetate.

8. The combination of claim 7, in which the aqueous latex adhesivefurther includes a latex plasticizer.

9. The combination of claim 7, in which the aqueous latex adhesivefurther includes a tackifying resin.

10. The combination of claim 7, in which the aqueous latex adhesivefurther includes a biocide.

11. The combination of claim 7, in which the aqueous latex adhesivefurther includes a fire-retardant additive.

1. A DECORATIVE WALL COVERING FOR INSTALLATION UPON A RIGID WALL FORIMPARTING A FINISHED SURFACE TO THE WALL CONSISTING ESSENTIALLY OF: A. AFLEXIBLE LATH OF MESH MATERIAL, B. A SUBSTANTIALLY DRY SEMI-HYDRATEDFLEXIBLE GYPSUM LAYER BONDED ON SAID MATERIAL SUBSTANTIALLY COVERING ONESIDE OF SAID LATH, C. A SUBSTANTIALLY UNIFORM AQUEOUS LATEX ADHESIVECOATING ACROSS AN EXPOSED SIDE OF SAID GYPSUM LAYER FOR SECURING SAIDWALL COVERING TO SAID RIGID WALL AND HYDRATING SAID GYPSUM, D. SAIDRATIO OF AQUEOUS LATEX ADHESIVE TO GYPSUM IS SUCH THAT SAID AQUEOUSLATEX ADHESIVE SUPPLIES ABOUT THREE PARTS BY WEIGHT OF WATER FOR ABOUTTEN PARTS OF WEIGHT OF GYPSUM, AND E. SAID SEMI-HYDRATED FLEXIBLE GYPSUMBEING OF SUFFICIENT THICKNESS THAT SAID AQUEOUS LATEX ADHESIVE AFFORDS ASUFFICIENTLY CONTROLLED AMOUNT OF WATER TO HYDRAATE SAID GYPSUM AND FORINVERTING SAID LATEX ADHESIVE, WHEREBY THE WALL COVERING MAY BE SHIPPEDAND STORED IN ROLLS PREPARATORY TO INSTALLATION UTILIZING SAIDAPPLICATION OF AQUEOUS LATEX ADHESIVE.
 1. A decorative wall covering forinstallation upon a rigid wall for iMparting a finished surface to thewall consisting essentially of: a. a flexible lath of mesh material, b.a substantially dry semi-hydrated flexible gypsum layer bonded on saidmaterial substantially covering one side of said lath, c. asubstantially uniform aqueous latex adhesive coating across an exposedside of said gypsum layer for securing said wall covering to said rigidwall and hydrating said gypsum, d. said ratio of aqueous latex adhesiveto gypsum is such that said aqueous latex adhesive supplies about threeparts by weight of water for about ten parts of weight of gypsum, and e.said semi-hydrated flexible gypsum being of sufficient thickness thatsaid aqueous latex adhesive affords a sufficiently controlled amount ofwater to hydrate said gypsum and for inverting said latex adhesive,whereby the wall covering may be shipped and stored in rolls preparatoryto installation utilizing said application of aqueous latex adhesive. 2.The combination of claim 1, in which the aqueous latex adhesive includesa latex plasticizer.
 3. The combination of claim 1, in which the aqueouslatex adhesive includes a tackifying resin.
 4. The combination of claim1, in which the aqueous latex adhesive includes as thickener.
 5. Thecombination of claim 1, in which the aqueous latex adhesive includes abiocide.
 6. The combination of claim 1, in which the aqueous latexadhesive includes a fire-retardant additive.
 7. The combination of claim1, in which the aqueous latex adhesive comprises a water emulsion ofpolyvinyl acetate.
 8. The combination of claim 7, in which the aqueouslatex adhesive further includes a latex plasticizer.
 9. The combinationof claim 7, in which the aqueous latex adhesive further includes atackifying resin.
 10. The combination of claim 7, in which the aqueouslatex adhesive further includes a biocide.